About the inconsistency of parameter types in function declaration and invocation

Or the last one, because the old-style C function declaration can not specify the number and type of arguments, so the compiler does not check the function call.

Take a look at the following example:

#include <stdio.h>

int main (void)
{
	void foo ();
	void foo (double);
	char C =;
	Foo (c);
	return 0;
}

void Foo (double D)
{
	printf ("%f\n", d);
}

You'll notice that the program runs 0.000000.

The debug run will find that:

1. Because the Foo function is declared void foo (void), the argument C is not passed in at all;

2. Local variable D is a random value, my machine is 2.5463949521227207e-313, this number has exceeded the range represented by double so print out 0.000000

If you replace the declaration statement with a comment, you will find that the program runs 60.000000

Declaration and implementation are consistent, parameters can be passed, although calling Shishun is a char value, but the runtime enforces the type conversion to double.